Joint water stop



Aug. 25, 1964 G. BRECHIN JOINT WATER STOP Filed June 27, 1961 CHINmun/7w? GORDON L. BRE

United States Patent This invention relates to water stops for joints inpourable plastic materials, such as concrete.

It is often necessary to pour different parts or sections of concretewalls at different times, or to provide for the connection of a new wallto an old wall. In each case, the second or later pour of concrete isabutted against a surface of a previous pour. The new concrete containsa comparatively large volume of water, whereas the old concrete has setto a certain extent at least. As a result of this, the new concrete asit dries and sets shrinks relative to the old concrete, leaving a crackor space therebetween through which water can travel.

Water stops are employed in an effort to seal these joints in concretein order to prevent water from passing therethrough. However, the waterstops of the prior art are not completely satisfactory. One form ofprior water stop consists of a fiat strip of elastic material which ispartially embedded in the first pour of concrete, and projects outwardlyfrom the end thereof. This necessitates a split form at the end of theform for the first pour in order to allow the strip to project outwardlytherefrom. After the end form has been stripped away, the concrete forthe second section is poured and is supposed to embed the projectingportion of the strip. When this happens, the strip is embedded in theold and new concrete, and most strips have anchoring means in the formof ribs and the like along the edges thereof so that they are anchoredin the two wall sections. However, it quite often happens that theprojecting portion of the rip is flattened and displaced from its properposition during the second pour of concrete, in which case it is notanchored in said second pour and failure results.

Another form of prior water stop comprises a strip of elastic materialhaving staggered projections from opposite faces thereof that areembedded in the first and second pours of concrete. These projectionshave lateral ribs thereon to be sure they are anchored in theirrespective pours. With this construction, when the second pour shrinksrelative to the first, the main body of the stop is pulled away from thefirst pour. In addition to this, the material forming the projections iselongated so that said projections get thinner and contract relative tothe concrete in which they are embedded. Another disadvantage of thistype of Water stop is that a part thereof is subjected to a shearingaction since one face of said part is anchored to the oldconcrete andthe opposite face thereof is anchored to the new.

The present water stop is so designed that it cannot be displaced eitherduring the first or second pours of concrete at the joint where thewater stop is employed.

A water stop according to the present invention avoids the above-noteddisadvantages. It comprises a web strip having a pair of key legsextending longitudinally thereof and projecting outwardly from one ofits faces. choring means is provided on and projects from the oppositeface of said strip. In the preferred form of the invention, anchoringmeans is provided opposite each key leg. Said key legs are inclinedtowards each other to form a dovetail keyway therebetween. The anchoringmeans is adapted to be embedded in a first pour of concrete which coversthe outer surfaces of the key legs. It is preferable, although notabsolutely necessaryto provide a contractible core removably fitting inthe keyway when the. first concrete is poured to prevent .collapseofsaid keyway. This core is moved after the initial setting of the firstpour. When the second section of the wall is poured, some of theconcrete flows into the keyway to form a dovetail key therein. When thesecond pour begins to contract, the dovetail key moves longitudinally ofthe wall in a direction away from the first pour. This tends to stretchthe key legs which become thinner at this time, but the sides of the keyare inclined and they are moving towards inclined portions of the firstpour concrete to lessen the distance therebetween so that the key legsdo not pull away from the concrete along the opposite surfaces thereof.In the preferred form of the invention, each key leg is unobstructed onits outer surface, and has ribs on its inner surface projecting into thekeyway. Thus, the only portions (the key legs) of the water stop thatcan move when the second pour concrete contracts become more firmlygripped during the contracting action.

A preferred form of water stop is illustrated by way of example in theaccompanying drawings, in which,

FIGURE 1 is a perspective view of the water stop,

FIGURE 2 is a cross section through the water stop after the firstconcrete has been poured with the end form or bulkhead still in place,

FIGURE 3 is a view similar to FIGURE 2, but with the end form orbulkhead removed and ready for the second pour, and

FIGURE 4 is a view similar to FIGURE 3 after the second concrete hasbeen poured.

Referring to the drawings, If? is a preferred form of water stop whichis formed of a suitable elastomeric material, such as rubber orpolyvinyl chloride or other synthetic resin. The stop may be formed inany convenient manner, but it is usually extruded in the proper crosssectional shape so that it may be made any length and cut into pieces ofdesired lengths.

Water stop 10 includes a web strip 12 having opposite faces 13 and 14. Apair of key legs 19 and 20 extend longitudinally of the strip and extendoutwardly from face 14 thereof. These legs are preferably along theedges of the strip, as shown. Leg 19 has outer and inner surfaces 22 and23 which are substantially parallel. Although leg surfaces 22 and 23 maybe exactly parallel, it is preferable to have them converge a little ina direction away from strip 12 so that the leg is thinner at 25 near itsouter edge than at 26 near its inner edge where it joins the web strip.Furthermore, it is preferable that the outer surface 22 be unobstructedor comparatively smooth, as shown, and that inner surface 23 be providedwith one or more projections, such as a plurality oflongitudinally-extending ribs 28, extending longitudinally thereof.

Key leg 20 is shaped in the same manner as leg 19. Leg 2%) has a smoothor unobstructed outer surface 30, and an inner surface 31 with aplurality of longitudinallyextending projections or ribs 32 extendingoutwardly therefrom towards ribs 28. Leg 20 may also be thinner at 35near its outer edge than at 36 near its inner edge where it joins web12.

Key legs 19 and 20 are inclined towards each other to form a dovetailkeyway 39 therebetween. Although various angles of inclination may beused, it is preferable to incline each key leg from-3 to 7 .oif normaltoweb strip 12. In FIGURE 2, line 42 represents the general incline of leg19 relative to the horizontal centre line 43 of web 12, while line 44 isnormal to the latter centre'line. Angle 45 represents the angle ofincline of the key leg relative to normal to the web strip.

It is preferable to provide nailing flanges 48 and 49 along the outeredge of legs 19 and 20 and extending laterally therefrom.

Anchoring means is provided on webstr-ip 12 projecting from face 13thereof. It is preferable to provide anchoring means opposite each ofthe key legs 19 and 20. In

this example, the anchoring means comprises laterally-- spaced anchorlegs 52 and 53 extending along strip 12 and projecting outwardly fromface 13' thereof, said legs 52 and 53 being respectively opposite keylegs 19 and 29. Leg 52 is formed with inner and outer surfaces 55' and56 which may be parallel, but'preferably diverge outwardly from strip12, as shown. Surfaces 55 and 56, are preferably formed with projections58 and 59 extending outwardly therefrom, said projections preferablybeing in the form of ribs extending longitudinally of their respectivesurfaces. Anchor leg 53 is shaped the same as leg 52, and preferably haslongitudinally-extending ribs 62 and 63 on its inner and outer surfaces,respectively.

The water stop It is substantially H-shaped in cross section, as clearlyshown in FIGURES 2 to 4. When it is desired to make a concrete wall intwo or more sections, parallel forms 66 and 67 are erected for the wall,and an end form or bulkhead 63 is provided between these forms where thefirst pour of concrete is to end. Water stop is secured to a face ofbulkhead 63 in the area where the first concrete is to be poured. Thestop is usually nailed to the bulkhead, and it is preferable to usespecial nails 78 for this purpose, said nails being driven throughflanges 48 and 49 of the stop. Each nail has the usual head 71 on oneend, and a special head 72 spaced from the first head. When a nail i0 isdriven through one of the nailing flanges into the bulkhead, head 72engages said flange while a portion of the nail and head 71 project awayfrom the bulkhead, see FIGURE 2. Although not absolutely necessary, itis preferable to provide a contractible core 76 in keyway 39 between keylegs 19 and 2%. Although any form of contractible core may be used, itis preferable to use a plurality of filler strips formed of rubber,plastic or other suitable material for this purpose. In this example,three filler strips 73, 79 and Bil are used. Each filler strip iswedge-shaped in cross section, see FIGURE 2, and they are alternatelyarranged side by side so that they fill keyway 39 of the water stopinside bulkhead 68. This contractible core prevents legs 19 and 2% frombeing pressed inwardly out of their proper positions when concrete ispoured into forms 66 and 67 around the stop. This first pour of concreteis indicated at 82. It will be noted that the first pour of concreteembeds anchor legs 52 and 53, the ends of nails 74 and covers outersurfaces 22 and 30 of key legs 19 and 2%.

After the first concrete 82 has set to some extent at least, bulkhead 68is removed. During this operation, it is pulled away from nails 70 andthe water stop, leaving core 76 exposed. This core is contracted andremoved by first removing strip '79, after which strips 7 3 and 86 maybe moved towards each other and then withdrawn from keyway 39. The waterstop as shown in FIGURE 3 is now ready for the second pour.

The next concrete 85 is poured into forms 66 and 67 and flows intokeyway 39 to form a dovetail key 87 therein. This key is relativelylarge and projects well into the first pour concerete 82. As concrete 85starts to dry and set, key 87 tends to move in the direction of arrows89 and 90 in FIGURE 4. This key has sides 92 and 93 that aresubstantially parallel to surfaces 94 and 95, respectively, formed inthe first concrete 82 by the outer surfaces of key legs 19 and 20. Asthe key moves in the direction of arrows 39 and 90, it tends to movelegs 19 and 20 in the same direction owing to the dovetail shape of thekey and to ribs 28 and 32. As the outer surfaces 2?. and 30 of the keylegs are smooth, said legs can move with the key without danger ofshearing since they are not anchored to first pour concrete 82. Anchorlegs 52 and 53 are firmly anchored in concrete 82 so that they preventstrip 12 from being pulled away from said concrete during this action.This means that legs 19 and 26 are stretched as the second pour concretecontracts. How'- ever, the side surfaces 92 and 93 of key 87 are movingtowards the surfaces 94 and 95 of the first pour concrete so that as thekey legs get thinner, the spaces in which they are located also getthinner and therefore said legs are not pulled away from the concrete,In fact, as the contraction takes place, said key legs are more firmlygripped by the concrete. Thus, the contraction of the second pourconcrete does not result in any portion of the water stop being pulledaway from or otherwise separated from the surrounding concrete. At thesame time, the portions of the water stop between the old and newconcrete and not subjected to any shearing action.

As stated above, it is preferable that key legs 19 and 20 are inclinedfrom 3 to 7 off normal to web strip 12. It has been found that 5produces the best results. The reason for this is that if the incline istoo little, the inclined side surfaces of the key do not movesufficiently towards the opposed inclined surfaces of the old concreteto maintain a tight grip on the key legs as the latter contract whilethey are being stretched. On the other hand, if the angle of incline istoo great, the inclined sides of the key will compress the key legsuntil they become substantially solid, at which time there is danger ofthd key breaking away from the main body of the second pour concrete.The use of the special nails 70 is desir able since said nails arefirmly anchored in the first pour concrete at the time the bulkhead 68is removed from the forms, and therefore, the water stop is notsubjected to any strain at this time.

With reference now to the drawings and in view of the foregoing remarks,it is readily apparent that the key to forming a seal between the firstand second pours is the angle of inclination of the surfaces of the keylegs and the foregoing discussion of the general angle of inclination ofthe key legs themselves must be understood in this light. In the firstplace, the second pour of concrete must form a dovetail in the keywayprovided because, if this were not so, the second pour would be free topull away from the water stop. Therefore, the inner surface of each keyleg, which forms the shape of the second pour dovetail, must form anacute angle of less than 90 with respect to web strip 12. Second, theouter surface of each key leg must be inclined at less than 90 withrespect to the web strip because, if this were not so, irrespective ofthe shape of the dovetail, movement of the second pour would never causecompression of the water strip disposed between the pour thus defeatingthe whole purpose of the device-the provision of a stop compressedbetween the first and second pours. It is not, of course, necessary thatthe surfaces of the key legs be tapered as they may obviously beparallel without losing compression. However, each of those surfacesmust be disposed at an angle of less than 90 with respect to the webstrip. Specifically, the preferred angle of inclination is from 3 to 7off normal or 83 to 87 with respect to web strip 12. Thus, where the keyleg surfaces are parallel, each will be inclined within this preferredrange. Where the legs are tapered slightly, although the generalinclination of the key leg will remain at 83 to 87, the surfaces of thekey legs may vary therefrom somewhat depending on the degree of taperutilized. 7

What I claim as my invention is:

1. A water stop for joints in pourable plastic materials such asconcrete, comprising a web strip having first and second planar faces, apair of laterally spaced anchor legs integral with said web strip andprojecting outwardly from said first surface, a pair of key legsintegral within said web strip and projecting outwardly from said secondsurface in substantial alignment with said anchor legs, said water stopbeing adapted to be imbedded in a first pour of plastic material suchthat the anchor legs, first web face and outer surface of said key legsare covered with said firstpour, projecting means on eachanchor'leg'to'am chor said legs in said first pour, each of said keylegs having an outer surface disposed at an angle of less than withrespect to said second web face and an inner surface disposed at anangle of less than 90 with respect to said second Web face to form adovetail keyway between said key legs adapted to receive a portion of asecond pour of plastic material such that a formed dovetail of saidsecond pour material is disposed within said keyway, projections on theinner surface of each key leg to anchor said inner surface to saidsecond pour material, and said outer surface being smooth and free ofprojections opp0 site said projections whereby on relative movement ofsaid second pour away from said first pour, each key leg remainsdisposed between said first and second pours with the inner surface ofsaid key leg anchored to said second pour through said projections andwith the outer surface free to move relative to said first pour due tothe absence of projections on said outer surface.

2. A water stop for joints as claimed in claim 1 wherein the innersurface of said key legs is inclined relative to said outer surface suchthat the key legs are tapered to 6 be thinner at the outer ends thereofremote from said second web face.

3. A water stop for joints as claimed in claim 1 wherein the key legsare each provided with nailing flanges at the ends of the outer surfacesremote from said second Web face.

4. A water stop for joints as claimed in claim 1 comprising one paironly of said anchor legs and key legs.

5. A water stop for joints as claimed in claim 1 wherein the inner andouter surfaces of each key legs are inclined at about 83 to 87 withrespect to the web strip.

References Cited in the file of this patent UNITED STATES PATENTS2,798,373 Harza July 9, 1957 2,937,065 Harza May 17, 1960 FOREIGNPATENTS 799,426 France Apr. 4, 1936 861,251 Great Britain Feb. 15, 1961

1. A WATER STOP FOR JOINTS IN POURABLE PLASTIC MATERIALS SUCH ASCONCRETE, COMPRISING A WEB STRIP HAVING FIRST AND SECOND PLANAR FACES, APAIR OF LATERALLY SPACED ANCHOR LEGS INTEGRAL WITH SAID WEB STRIP ANDPROJECTING OUTWARDLY FROM SAID FIRST SURFACE, A PAIR OF KEY LEGSINTEGRAL WITHIN SAID WEB STRIP AND PROJECTING OUTWARDLY FROM SAID SECONDSURFACE IN SUBSTANTIAL ALIGNMENT WITH SAID ANCHOR LEGS, SAID WATER STOPBEING ADAPTED TO BE IMBEDDED IN A FIRST POUR OF PLASTIC MATERIAL SUCHTHAT THE ANCHOR LEGS, FIRST WEB FACE AND OUTER SURFACE OF SAID KEY LEGSARE COVERED WITH SAID FIRST POUR, PROJECTING MEANS ON EACH ANCHOR LEG TOANCHOR SAID LEGS IN SAID FIRST POUR, EACH OF SAID KEY LEGS HAVING ANOUTER SURFACE DISPOSED AT AN ANGLE OF LESS THAN 90* WITH RESPECT TO SAIDSECOND WEB FACE AND AN INNER SURFACE DISPOSED AT AN ANGLE OF LESS THAN90* WITH RESPECT TO SAID SECOND WEB FACE TO FORM A DOVETAIL KEYWAYBETWEEN SAID KEY LEGS ADAPTED TO RECEIVE A PORTION OF A SECOND POUR OFPLASTIC MATERIAL SUCH THAT A FORMED DOVETAIL OF SAID SECOND POURMATERIAL IS DISPOSED WITHIN SAID KEYWAY, PROJECTIONS ON THE INNERSURFACE OF EACH KEY LEGS TO ANCHOR SAID INNER SURFACE TO SAID SECONDPOUR MATERIAL, AND SAID OUTER SURFACE BEING SMOOTH AND FREE OFPROJECTIONS OPPOSITE SAID PROJECTIONS WHEREBY ON RELATIVE MOVEMENT OFSAID SECOND POUR AWAY FROM SAID FIRST POUR, EACH KEY LEG REMAINSDISPOSED BETWEEN SAID FIRST AND SECOND POURS WITH THE INNER SURFACE OFSAID KEY LEG ANCHORED TO SAID SECOND POUR THROUGH SAID PROJECTIONS ANDWITH THE OUTER SURFACE FREE TO MOVE RELATIVE TO SAID FIRST POUR DUE TOTHE ABSENCE OF PROJECTIONS ON SAID OUTER SURFACE.